Forests

One of Japan's greatest resources is, of course, its forests. Wood was the basis of most of the building and machinery associated with industry and hydrology in Japan's pre-industrial past.

At the end of the 1990s, Japan was the world's largest importer of timber products (approximately 20 percent of the world's total trade volume of timber), with the US not far behind.64 Ironically, forests cover 24,621,200 ha (246,212 km2) of Japan's land, which totals 37,652,000 ha (376,520 km2).65 Therefore, 65.4 percent, very nearly two-thirds of Japan's land area, is forested. Much forested land is mountainous, therefore less likely to be cleared for other uses.

Koichiro Koike of Shimane University in Matsue City suggests that 60 percent, or 15 x 106 ha, of Japan's forests could be sustainably managed and harvested to provide wood biomass and other products. The energy value of the harvested wood can be calculated as follows:66

Average annual growth per ha for Japanese forests 13.8 tonnes

Multiply by 0.4 to eliminate leaves and branches 5.52 tonnes

Multiply by 15 x I06 ha for total harvested weight 82.8 x I06 tonnes

Multiply by 18.84 x I09 J/tonne to obtain energy value in J 1.56 EJ

As Japan's total primary energy supply in 1998 was 22.7 EJ, this 1.56 EJ represents nearly 7 percent of current primary energy - not bad for a potentially fully sustainable resource that is hardly tapped at all now. However, burning is not the only thing you can do with wood. At 127 million people, the 82.8 million tonnes of trunk wood harvested would provide 650 kg of wood per person per year, some of which would be needed to construct homes, furniture, and so on. A typical Japanese house is about 100 m2 in floor area and the wood needed to construct it is about 20 m3. Since the density of timber grown in Japan is on average 0.6-0.65 g/cm3, about 12-13 tonnes of wood are needed to construct the house (though there is no particular reason why houses should be this size in the future). If 650 kg of wood were harvested per person per year on average, to build this house would take one person 20 years.67 That assumes the sole use of timber is house-building, but if there are four people in the family, the house can be rebuilt in 20 years using only a quarter of their "ration" of wood. If houses are built to last for 30 or 40 years, then even at the current population level, housing can be supplied on a sustainable basis from Japan's forests. We should bear in mind though that not all kinds of trees (wood) are suitable for construction; the difference in geographical distribution of forests and time necessary for forest growth and management makes this merely a "theoretical" calculation (see below), and all other requirements for house-building (including carpenters, tools, and so on) may not be freely available.

We still have not taken into account the remaining 60 percent of the growth (8.28 tonnes/ha of leaves and branches) that can be used for fuel or composted for maintaining agricultural land fertility, though some of it should remain in the forest to help maintain soil fertility there.

The problem with all of this biomass is that it will need to travel to where it is to be used, which must mean locally, or within easy reach of a suitable waterway, as other forms of long-distance transportation would use more energy than represented by the wood transported. That means that people who live near forests will be relatively better served. Ibaraki Prefecture, where I live, for example had a population of very nearly 3 million in 1998. Its forested area was 195,200 ha. Performing the above calculation gives 1,078,000 tonnes of sustainably harvestable wood, or 360 kg/cap/year (plus the leaves and branches). People in Hokkaido will be better off (but they will need to burn more as the winters are more severe) while people in Tokyo's Shinjuku District, where there is hardly a tree to be seen, will not be so well off, though it might be easier to find shelter there.

What if there is a severe food shortage? Tokyo Shinbun68 reports that rural inhabitants of the DPRK (North Korea) are clearing forests to make fields for growing food. The fields thus created become the property of the farmer. A man from North Hamyong Province, in the northeast corner of the DPRK, said in an interview that almost all the forests within 10 km of his village had been cleared and that maize and vegetables were being grown on the new fields. The ownership of the fields was being quietly acknowledged by the authorities and a tax consisting of part of the crops was paid. Forest clearing and the need for fuel had resulted in nearly all the trees being felled, and this was causing floods and mudslides. It is therefore essential that Japanese people learn to appreciate the absolute necessity of maintaining their forests in as large an area and in as good condition as is humanly possible, even if the temptation to cut for fuel and clear for food-producing fields is strong.

Clearcutting followed by the establishment of tree plantations (generally fast-growing conifers) is not a good idea either. Large-scale tree plantations were carried out in many places in Japan in the 1950s and 1960s with deleterious effects.69 These included the replacement of valuable native ecosystems; destruction of animal and plant biodiversity; depletion of water resources; and alteration of mineral content in water runoff, with a generally adverse effect on local agriculture, reversible only in the timescale of centuries.

What needs to be done (or not done) is reasonably clear. The ability to carry out forest protection and management in Japan in coming decades depends on whether the Japanese can become aware of how much their forests mean to them in terms of long-term survivability. In the case of a sudden food and energy crisis, as occurred in the DPRK in the mid-1990s, forest resources will come under immense pressure. Only a great deal of wisdom and foresight can prevent an ecological tragedy from occurring.

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